2009 Nissan GT-R Horsepower: The Truth

Yes, we have already dynoed Nissan's GT-R and we made some very controversial claims as to the true power output of said GT-R. The unknown in that test was the elusive "driveline losses." That's the amount of power lost to inertia of spinning parts like gears and driveshafts and friction in the transmission, U-joints, axles, etc., which have traditionally had to be estimated. We used the conservative estimate of 15% that's usually used for simple manuals, but this one uses twin hydraulically actuated clutches, includes all-wheel drive, with two separate prop shafts, so we considered our estimate conservative. Our Dynojet inertia-type machine indicated a mean output of 430.6 hp at 6700 rpm and 425.3 lb-ft at 3900 rpm, which we interpreted as 507 hp and 500 lb-ft after accounting for the 15% loss.

We were recently contacted by a Motor Trend reader who saw our first GT-R dyno story. He said he had a new type of dyno that was able to compute the drivetrain losses directly and accurately, removing the guesswork. How, you might ask, does it manage this? That's what we're here to tell you.

When you arrive at Hyper Power International and first see this new dyno, it looks like any other inertia-type dynomometer -- four big rollers, wires, computer screens, the usual -- and like any other dyno you start the process by strapping your vehicle down. Once secured, the next step is to do a gearing calculation run. This provides the dyno with the engine rpm in reference to the roller speed thus eliminating the need for an rpm pickup, which can provide inaccurate information.

Just before we make our first run the ambient weather conditions are entered into the dyno computer. While we were there the temp ranged from 68 to 72 deg, humidity ranged from 44% to 49%, and the barometric pressure ranged from 29.55 to 29.61 in. of mercury. Again, all this is operating norm for dyno runs. Now it's time for some power pulls.

First pull:Ending at 6500 rpm, our first run's results were: 485.9 hp @ 6116 rpm and 469 lb-ft @ 3834 rpm (corrected for weather and subtracting the measured losses).Second pull:Again, going to almost 6500 rpm the second run gave us 485.5 hp @ 5984 rpm and 475 lb-ft @ 3717 rpm. This is only a 0.4 hp (0.08%) difference from run one with the torque differing by 6 lb-ft (1.2%).Third pull:The final run provided us with 483.4 hp @ 6106 rpm and 466 lb-ft @ 3811 rpm, a difference of 0.4% for hp and 1.9% for torque.Averaging the runs gives us a Hyper Power rating of 485 hp @ 6050 rpm and 470 lb-ft @ 3800 rpm.

Pull two

Pull three

So, how did Hyper Power USA measure our driveline drag? At the end of a pull, the computer instructs the operator to put the vehicle in neutral, the dyno then measures the rate at which all the rotating parts slow down, which is directly related to friction and inertia. Our instruments found the loss to be exponential -- as the speed grew so did the loss. We saw a loss of 23 hp at 50 mph and 84 hp at 100 mph. Over the three runs we saw a driveline loss range from 88 hp to 93 hp. Thus, there is no longer the need to guess at a percentage, Hyper Power Dynamometer measures it and gives you an actual figure generated by the engine and consumed by the drivelineHere is an example of why using a fixed percentage number for drivetrain loss is flawed in calculating measured dyno horsepower:

Take a turbocharged vehicle, dyno runs put its output at 400 hp and 400 lb-ft of torque. Applying 15% for driveline loss yields an actual output of 460 hp and 460 lb-ft of torque. Now, take same vehicle, turn up the boost on the turbo. The dyno pulls now have the same exact vehicle rated at 600 hp and 600 lb-ft torque, apply 15% driveline loss, actual output is 690 hp and 690 lb-ft torque. Why does the loss increase with more horsepower? It's the same exact car, just with the boost now turned up. The loss should be the same; whatever the horsepower number is, it's the same driveline.So, what does this all mean? Well, it suggests that Nissan is basically telling the truth with their horsepower numbers, but the torque numbers are conservative by about 40 lb-ft.So what does this tell us about Nissan's mighty Monster's miraculous performance? It suggests that the super-short gearing, the twin-clutch gearbox's uninterrupted torque flow, and the amazing (and also controversial) launch-control system are more responsible for generating the incredible acceleration numbers than hidden unclaimed horses.

ajn73nova, answer to your question."i got a quick comment/questionhow can this test account for losses through the transmission which is cut out of the counting for inefficiency losses when it is put into neutral?shouldnt that be calculated in also which would then attest to nissan lying with hp as they did with their torque!"Answer:You need to understand that the tranny gears on the output (wheel side) and input (engine side) shafts are always meshed. In neutral, all the rotating components of the tranny except for the input shaft is spinning and therefore will account for most of the losses in the tranny. When a gear is selected only then is the output and input shafts locked together according to the ratio of the gear selected. Hope that helps.

So initially you had a wheel hp to flywheel hp ratio of (F-D)/F and afterwards you have a wheel hp to flywheel hp ratio of (1.5F-1.5D)/1.5F = 1.5(F-D)/1.5F = (F-D)/F . In other words, even though you increased the engine's hp by 50% the drive train loss also increased by 50% and your whp to flywheel hp ratio remains the same.

I'm not an engineer but I think the third to last paragraph in this article is incorrect.For a rotating system Power = (moment of inertia)*(angular acceleration)*(angular speed)orangular acceleration = Power/[(moment of inertia)*(angular speed)].So if you increase the engine's flywheel hp by a factor of 1.5 at a certain rpm (or angular speed), then the angular acceleration that you will see at that rpm will be increased by a factor 1.5. Your drive train loss will also increase by a factor of 1.5 at that same rpm because you are accelerating it at 1.5 times the rate that you did previously. (The power consumed by the drive train is proportional to angular speed and angular acceleration and the angular speed is the same as before.) So if F is the initial flywheel hp and the drive train loss at a given rpm is D, then you have F-D at the wheels. Now if you increase the flywheel hp by a factor of 1.5 at a given rpm, then the drive train loss at that rpm will be 1.5D and you have 1.5F-1.5D at the wheels.

"We couldnt use launch control on a dyno so it would be irrelevent any how."Launch control doesn't create power so the peak hp number shouldn't change. Now that we know with some certainty what this GT-R's hp and torque numbers are it would be nice to associate them with some acceleration times. If this car's acceleration time is significantly slower than other GT-R acceleration times, it still leaves questions.

#Why does the loss increase with more horsepower? It's the same exact car, just with the boost now turned up. The loss should be the same; whatever the horsepower number is, it's the same driveline.#1: It's the same driveline, BUT you spool it up faster = more loss2: Why does transmissions and rear ends get hotter with more power if the loss is constant? = more friction = more loss = more heat3: would the car still have 94 hp drivetrainloss if you turned the power down to 100 hp? -15% sounds alot closer.About 10-12% loss is close on jdm rwd's w/mt, either they are stock or boosted 300%Sry my bad english

There are many problems with that dyno, and I don't think it gave us a better idea of how much power the GTR makes. The dyno probably does correct for the friction of its own rollers, but if they overlooked that, then you can add a decent amount of horsepower. By measuring the car in nuetral, you do miss several friction points between the flywheel and transmission parts no longer under load. Gears are where some of the greatest amounts of power are lost. The biggest flaw is that it uses deceleration of the vehicle. Deceleration is a factor of friction and intertia. The problems are as follows: Friction is not constant with varying speeds making it impossible to accurately estimate using that method. Additionally, while intertia has nothing to do with the amount of power lost in the drivetrain, to calculate the friction, you'd need to know the exact moments of inertia of EVERY moving part in the drivetrain of any vehicle strapped to it to try to get an accurate calculation.

the GTR is amazing, sure the ZR1 is faster in a straight line, but the Nissan has a well-suited back seat, AWD, and is flat out much nicer looking. The Nissan is gorgeous, meanwhile the Corvette has been looking the same since 05 and also, has never even looked that good when the new style first came out. I gotta go with Nissan > Corvette.Also, jybt, i agree with you on the first part of your statement, but you are wrong in the fact the Jaguar XF is better than the BMW 5. There is no way the XF is best in class. Sure, its a massive improvement over the crappy S-type but it cant stack up against the BMW 5, Merc E, Lexus GS, or Audi A6. t won only bc its the newest car of the group, and the editors are of course going to be more excited to drive the Xf cuz they havent ever before

Just talked went to a Nissan dealership yesterday and they said it gets slightly different bhp output readings because each engine is handbuilt, and no one dynamometer is exactly the same as another. So the car they tested earlier that got 507 bhp couldve gotten anywhere from 480-500+bhp on this dyno. No one car has the same exact output, that goes for all cars not just the GT-R.

This isn't surprising. But if MT dyno tested the same vehicle that ran the 'Ring, OR the Pre-production models that posted 124mph trap speeds, it would dyno higher, GUARANTEED.Also, I agree 15% seems conservative for AWD. I would put it closer to 18%.

I'm happy with the GT-R (side note: saw Godzilla again today. This was a different specimen, even!), but I am not happy with the GT-R, Forester (which also deserved its win), and F-150 sharing the three OTY podiums. That's what I've always meant by these comments; apparently some people are misunderstanding me.

i think its funny how people still manage to bash the gt-r even when they are proven wrong. nissan didnt lie, they never did. i think this whole thing about the gt-r and the ring is ridiculous as well. nissan has no reason to lie to the general public...it has its reputation to think about. in any case props to the gt-r the legend of godzilla will continue to grow and be greater than any other car ever.

And basically most of the roads in Europe are 2-lane besides their highways. Just about every turn I make here in the heartland is a 90 degree left or right hand turns, the curviest road here is a snaky on/off-ramp to I-40, I have seen a few wrecks there,not happen but I saw the aftermath, and one was a rolled over Chevy Tahoe in the ditch that T-boned an older 2-door Ford Focus, another was a 3-5 year old VW GTi that had understeered into the same ditch.

Whoa there,TurboGSX04.You said,"im talking drag race, who cares about track racing"Nobody else outside the US give a damn about drag racing other than Australians. The best place to race is a track,where man and machine are fighting together,requiring skills. Drag racing is merely launching the car in a straight line. And usually track cars drive better than drag cars because there ARE CORNERS. I don't think you know anything about them,so please keep your mouth shut.

Turbo you twit, who cares about track racing lol. In a drag race whats the point anymore? In a track race where more skill is need than shifting at the right time. Come on, the ACR is a real beast. Get off your retirement dream.

What about the fact that different types of chassis dynos have been known to result in different numbers? But no surprise that it has been underrated.And for those saying this is somehow proof of its ring lap.....no, its not.

Fail. Fail, fail, fail.You're quite proud of failing, aren't you, MT?You voted the Forester SUVOTY because it's the right SUV for the times, then vote the GT-R COTY, saying that it beats out the "cars for the times", and then switch again by saying the F-150 deserves TOTY because it's the right truck for the time.You also downgrade the Jaguar XF in the competition because it is "not the best in its class" when you voted it as such in Private Reserve Cabs. You claim its handling is not as good as the BMW 5-series with no ride card to play in response, which implies that the 5-series is better than the XF. In PRC, XF won 1st, 5 won 3rd. MT Fails.

Some people are correct, the GTR vs Corvette battle is getting old. Finally, further proof that the Nissan's claims of hp and torque have been proven to true and that nissan was not inflating the power ratings. As for the ring times, its said that companies like porsche try to disposition Nissan's time at the "Ring". But hey, there just scared of the mighty GTR. I'd personally choose this car over any exotic including the zr1. Yes the zr1 is fast however looks like everyone elses vette on the street and is poorly constructed compared to other supercars. Besides it has mountains of cheap plastic inside.Comparing the zr1 and a viper srt10 there performances are pretty close and the viper is alot cheaper. But besides that point, the Gtr is a better choice of car than either zr1 or viper.

This GTR vs Corvette thing has gotten old! The GTR is simply a game changer for everybody that claims to build a so called Super Car. This car manages to get to 60 in under 4 sec wether or not u use the launch control. It tops out at 190+ with its short gearing and all. It has a back seat and AWD, so it can cary 3 others even in winter weather. Did I mention it cost $70k before the KY lubricant application of course.I have respect for any automaker than can accomplish such a feat. The Corvette in all its iterations is an AWESOME car that has finnaly EARNED/gotten respect from all car enthusiast from countries all over, not just here in the USA! Why arent any of you comparing it to the Snob Mobile 911,another great car(I want).If I had the cash of Jay Leno I would have 1 of each amoung my many other treasures.

Catapult5 if memory serves me right the vette needs a launch around 2300 rpm to really get going, so while the clutch may not handle 4500 rpm launches well it doesn't need to in order to go very quickly. However the GT-r is an epic car, just not my personal favorite.

im not jumping down anyones throat. ill give credit where credit is due. gm generally does make better cars than toyota and nissan in the last 10 years. the only time they didnt have better cars was the late 70's to mid 90's

I agree with CarNYC. The ZR1 is fast, probably even the fastest of all the cars mentioned on this wall. But it sure as hell should be fast....its got 640hp. The ZR1 is a great car and epitomizes a great sports car....but nonetheless the GTR should be given its share of respect as it marginally keeps up with the ZR1 with less than 500hp, is heavier, has AWD, and has a back seat....just like what Alikat states. And for all those claiming the GTR's transmission is crap has no idea about transmissions in the first place. Every sports car has warranty exclusions for trans damage stemming from abusive drivers. Heck, even motortrend, this site, has posted an article saying that the GTR trans problem is merely an idiotic myth, created by idiotic bloggers, and ultimately believed by idiots.

Guys, Guys, can we all get along?Yes, the ZR1 is faster then the GT-R and it would beat it any time you rece them. But heck, the ZR1 has way more HPs than the GT-R, 640 to be exact.The ZR1 deserves it dues for being one of the fastest super cars in the market. Now, lets give the GT-R it dues for what it does and for what it has done in all the blogs accross America. The GT-R has been the most talked about car in recent history and against all odds it has earned its respect. So guys, GIVE THE GT-R IT DUES. PS. There is got to be a reason why it won MTCOY.

the launch control feature is what ur paying for. id rather have Zo6. i hate awd its not for drag racing. ill agree its the quickest 0-60 but it loses it power top end cuz of the awd. if the launch control cant handle what it was designed to do then i cant give much props to the car.

Galaxie, the GT-R over at nagtroc that has more than 600 hp runs 10s and the tranny held more than 100 launches. Don't act like every transmission is a grenade since only 6 have blown total and all were abused in some way. I wonder how many 4500 rpm clutch dumps the ZR1 can hold?

Finally this nonsense about over-boosting and ringer cars can be put to rest. The ZR1 beats the GT-R handily... and it should with almost 640hp. That the Nissan manages to get so close to it and other thoroughbred sports cars with less than 500hp and an extra couple hundred pounds of AWD and back seat is an amazing feat (and still pulling a sub 4 second 0-60 time without the launch control). People need to just give this car it's due. It's earned it.

TurboGSX04 & thetransamkidbased from previous articles on MT they did a test on the gt-r with the launch control off and did 0-62 in less than 4 seconds, also there was a guy who upped the power on his gt-r to 600 hp and did 100 launches with the LC and it only failed after that 100 imagine if this car had the same power as the zr-1, it would not need LC to beat it..:)

i got a quick comment/questionhow can this test account for losses through the transmission which is cut out of the counting for inefficiency losses when it is put into neutral?shouldnt that be calculated in also which would then attest to nissan lying with hp as they did with their torque!

actually the king of the sports car is the zr1. the gtr is nothing without the launch control that grenades tranny's. the main component that sets it apart from the competition is its downfall, and a huge downfall at that

LOL! i knew motortrend was wrong. they just could not believe the performance of this car. it does not have a 20.0 litre V8, so that kinda of performance just seemed so unreal to them, Nissan had to be lying they thought to themselves. WRONG!!!